This invention relates generally to a machine for harvesting crops in a field and, more particularly, to a disc cutterbar having an operating width greater than the width of the crop harvesting mechanism operating rearwardly of the disc cutterbar.
In modern crop harvesting machines, such as those having rotary disc cutterbars, the desire is to increase the width of cut of the machines to reduce the length of time the machine is operated in the field. Crop harvesting machines, such as those used to harvest hay and forage crops, typically have a conditioning mechanism mounted rearwardly of the crop cutting mechanism to crack the stems of the crop and enhance drying, as is well known in the art. The width of the conditioning rolls is limited due to manufacturing constraints, operating tolerances and financial considerations. Accordingly, increasing the operating width of the cutting mechanism may not result in an equivalent increase in the width of the conditioning rolls.
Having the conditioning rolls with a transverse width less than the transverse cutting width of the disc cutterbar requires that the severed crop be conveyed laterally and inwardly in the header for a distance before being fed rearwardly into the conditioning rolls. A number of devices have been created to effect the conveyance of this severed crop. In one known configuration, a drive shaft mechanism extends downwardly from the superstructure of the header to attach to one of the disc cutters and provide driving power to the cutterbar, similar to that shown in U.S. Pat. No. 5,179,822, issued on Jan. 19, 1993, to McLean, et al. The positioning of this drive shaft mechanism within the normal path of crop movement further complicates the conveyance of severed crop toward the center of the header. The rapidly rotating drive shaft is subject to being unbalanced from an accumulation of severed crop in the shaft mechanism, especially in the universal joints required to permit a flexible movement of the cutterbar relative to the header superstructure. Mounting a crop conveying drum of the type known on the disc cutter does not present a viable solution to shielding the drive shaft mechanism as a large amount of internal clearance would be necessary to permit deflection of the drive shaft. Large clearances between the drive shaft and the drum allow entry of severed crop material and entanglement with the drive shaft mechanism.
In another configuration shown in U.S. Pat. No. 6,497,087, issued on Dec. 24, 2002 to Stiefvater et al., a crop conveying drum for a drive disc cutter mounted directly to the drive shaft mechanism to provide rotational power to the cutterbar, also known as a “tall drum,” is shown. The crop conveying drum assists in conveying severed crop material laterally from outlying disc cutters toward a central opening for the conditioning rolls. The crop conveying drum serves as a barrier to prevent severed crop from wrapping around and accumulating on the drive shaft mechanism but features an open configuration which minimizes the accumulation of debris between the drum and the drive shaft mechanism. The crop conveying drum is formed as a pair of mating segments, each forming a half of the drum, and features. Each segment has a pair of support bars vertically oriented and extending between generally opposing connecting flanges. A mounting bracket centrally and supported by the vertical support bars is formed to partially wrap around the drive shaft mechanism and allow connection thereto. The mounting bracket has holes therein for the passage of fasteners to connect the drum segment directly to the drive shaft mechanism so that the crop conveying drum rotates with the drive shaft mechanism. Upper and lower mating connecting flanges are fastened together to form the entire crop conveying drum rotatable with the drive shaft. A completed welded drum requires two weldments and six hardware joints. The welded design has proven to be difficult to maintain assembly tolerances and costly to manufacture.
Accordingly, it would be desirable to provide a device that would protect the drive shaft mechanism from being overloaded with severed crop material and assist in the inward conveyance of severed crop for feeding into the conditioning mechanism around the barrier presented by the drive shaft mechanism that feature a simplified design and installation to overcome the above problems and limitations.